The invention is directed to improvements in electromagnetically actuatable valves and in methods for manufacturing them.
In a known electromagnetically actuatable valve (U.S. Pat. No. 4,610,080), the magnet coil is surrounded by a metal valve housing of ferromagnetic material, for conducting the magnetic field lines. This is not only very costly because the manufacture of the metal housing is labor-intensive, but the valve also has a large diameter and is undesirably heavy, because for static reasons the wall of the valve housing is made thicker than is necessary for conducting the magnetic field lines. An intermediate part made of plastic is also disposed in the known valve between the valve housing and the valve seat body, which entails the risk that from thermal expansion or swelling of the plastic, the intermediate part might shift in position in such a way that the valve needle could jam, or the intended valve needle stroke between the armature and the core changes in some undesirable way.